Cosmetic products have been conventionally used for imparting good appearance to skin or the like. In addition, cosmetic products are used for protecting skin from drying by preventing transpiration of moisture from the skin and further conditioning the skin as well as giving good appearance to skin or the like.
Natural oils such as lanolin and castor oil and synthetic ester oils having water-holding ability have been widely used as raw materials for obtaining cosmetic products which can prevent skin from drying and condition skin. In particular, water-in-oil-type cosmetic products coat a skin surface with an oil film and have higher affinity to skin compared to oil-in-water-type cosmetic products, and are therefore widely used as cosmetic products that can prevent skin from drying and condition skin.
Conventionally, lanolin has been widely used as an oil of natural origin. Lanolin is derived from wool fat and has high affinity, adhesion, and humectant properties to skin. Furthermore, lanolin is excellent in water-holding and emulsifying properties. Therefore, lanolin has been widely used in basic cosmetics, makeup cosmetics, and many other cosmetic products (refer to, for example, Non-Patent Document 1).
However, the use of raw materials derived from animals is decreasing because of the recently occurred mad cow disease problems, and it is significantly decreased to directly use animal-derived raw materials in cosmetic products. In addition, natural products such as lanolin and castor oil have problems that a constant quality cannot be readily obtained and prices widely fluctuate. Thus, they are not stable raw materials in the quality and price.
Consequently, instead of natural oils, synthetic ester oils have been recently used. For example, ester compounds of 12-hydroxystearic acid and polyols (refer to, for example, Patent Documents 1 to 4) and ester compounds of 12-hydroxystearic acid polymers and polyols (refer to, for example, Patent Documents 5 to 9) have been developed. The synthetic ester oils disclosed in these Patent Documents can impart water-holding properties to products containing these oils.
However, water-in-oil-type cosmetic products prepared using the ester compounds disclosed in Patent Documents 1 to 7 have unstable water-holding states, and thereby the long-term stability and the pigment-dispersing properties of the cosmetic products may be deteriorated. Furthermore, though cosmetic products prepared using the ester compounds disclosed in Patent Documents 1 to 7 can well adhere to skin and also have waterproof-film-forming abilities and non-dyeing properties at certain degrees, it is desired to further improve these properties.
In addition, the ester compounds disclosed in Patent Documents 8 and 9 are emulsifying agents and do not have film-forming ability, which oils do. Furthermore, the amounts of these esters used in cosmetic products may be restricted depending on types of the cosmetic products.    Patent Document 1: Japanese Unexamined Patent Publication No. 52-48613    Patent Document 2: Japanese Unexamined Patent Publication No. 54-109917    Patent Document 3: Japanese Unexamined Patent Publication No. 55-57509    Patent Document 4: Japanese Unexamined Patent Publication No. 56-57509    Patent Document 5: Japanese Unexamined Patent Publication No. 56-108739    Patent Document 7: Japanese Unexamined Patent Publication No. 05-331023    Patent Document 9: Japanese Unexamined Patent Publication No. 2000-290232    Patent Document 6: Japanese Unexamined Patent Publication No. 64-90025    Patent Document 8: Japanese Unexamined Patent Publication No. 07-8781Non-Patent Document 1: Keshohin-Jiten (Cosmetic Dictionary), Maruzen, published on Dec. 15, 2003 (Heisei 15)